William t



(No Model.)

W T ARNOLD -BURGLARALARM SYSTEM.

Patented June 29,1897.

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UNTTED STATES PATENT EErcE.

VILLIAM T. ARNOLD, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE CHICAGOELECTRIC PROTECTIVE COMPANY, OF SAME PLACE.

BU'ReLARv-ALARM SYSTEM.

`SPECIFICATION forming part of Letters Patent No. 585,171, dated J une29, 1897.

Application filed December l5, 1896. Serial No. 615,813. (No model.)

T @ZZ whom it muy concern:

Be it known that I, WILLIAM T. ARNOLD, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Burglar-Alarm Systems,(Case No. 1,) of which the following is afull, clear, concise, and exactdescription, reference beinghad to the accompanying drawings,

ro forming a part of this specification.

My invention relates to burglar-alarm systems in which openings orobjects are protected by movable covers, and especially to those systemsin which the openings or objects x 5 are protected by sliding covers.

In a patent issued to Alfred Stromberg, No. 530,975, dated December 18,1894, is shown and described a burglar-alarm system of the classment-ioned in which a circuitzo closer is employed comprising a plungeradapted to be depressed by the cover, asa window-sash, to make Contactwith a circuitterminal and close the circuit, the plunger at the sainetime making contact with a contact-terminal to complet-e the circuit.This device being located upon the window-sill is in a position tobecome rusted, thereby affording poor contact. Moreover, since thewindow-sill is subject to considerable dampness, 3o currents have leakedfrom this device to adjacent iron construction, thereby affording a pathof low resistance which shunts the artificial resistance normally incircuit with the line, thereby causing a false indication or 3 5 alarm.

My invention has for one of its objects to overcome the defects in theStromberg system above set forth.

My invention will be more readily under- 4o stood by reference to theaccompanying drawings, in which- Figure 1 is a diagrammatic View of aburglar-alarm system equipped in accordance with my invention. Eig. 2 isa sectional plan View of a portion of the apparatus, taken on line 2 2of Fig. 1.

Like letters refer to like parts in both views.

My invention is shown as being applied to an ordinary window-openinghaving a suit- 5o able casing a. Within the structure and before theopening are vertically disposed two guides b, of wire or otherconducting material, anchored at b b. Vithin the guarded structure andbefore the Window-opening is placed a vertically-movable screen c, (inthis instance serving to protect the lower half only of the window,)provided with conductors adapted to guard the opening, as will be setforth hereinafter. The screen is provided with eyes c d, which inclosethe metallic 6o wires b b and guide the screen in its vertical travel.

Secured near the lower ends of the guides b h are two cone-shaped blocksof insulating material d d', supporting terminal plates d d, 65 whichmake contact with terminal springs e e, supported upon the screen c,when said screen is lowered in a position to protect the opening. Theinsulating-blocks d/ d extend slightly above the terminals CZ d, asshown. 7o When the screen is raised, springs e e are iirst brought intocontact with the exposed portions of blocks d d and then in contact withguides h b, causing an alarm in each instance if the circuits are incondition to protect the opening, as will be hereinafter set forth. Twocontact-terminals f fare mounted upon the window-casing and project overthe guides b b in a position to make contact therewith if the screenshould be pushed inwardly 8o from its normal vertical plane, as in theact of entering the guarded structure, whereby an alarm is sounded, aswill be set forth.

The line g, extending from the central station II to the protecteddistrict, includes the 8 5 line instruments t c" of the central-officeapparatus, which are grounded through a battery 2. Associated withmagnet c' is an armature k, adapted to close circuit at 7c throughasignal or alarm apparatus Z when 9o attracted. Associated-with magnetc" is an armature fm, adapted to close circuit at m', when unattracted,through signal apparatus n.

When the screen is lowered and the system is to be put in condition forprotecting the window, switch o is thrown from the daybutton o to theposition shown, whereby the continuity of the circuit from thecentraloffice battery i2 is completed through to the roo ground p at theprotected station, the current passing from line g, through the wire q,terminals e and (l upon the right of the screen, conductor r, terminalsd and e upon the left of the screen, and resistance s, to ground. Theresistance s serves to reduce the current emanating from battery 2.

A conductor t is united at t' to the line g, the plates ff constitutingterminals of this conductor. A second conductor a is connected betweenthe resistance s and ground and attached at uf n to the metal guides bb.

The magnets il i are wound to have similar magnetic strength. Thearmatures 7s and m are so adjusted that lnagnet fi will not attract itsarmature when resistance s is in circuit, while the armature of magnett" will be attracted thereby. It circuit from battery @"2 is opened,armature on will fall, thereby closing circuit at m through the signaln. If the current from battery 2 be increased by shunting resistance sfrom the line, armature 7c will be attracted, thereby completing circuitat la through the signal l.

If an attempt be made to gain access to the interior by thrusting thescreen aside, either or both of the plates f f will be brought intocontact with either or both of the metal guides l) l), therebyestablishing a shunt-circuit from t about the resistance s, thus@arising signal t to respond. Terminals ff and guides l) h thus form acircuit closing or changing device adapted to be operated by the screenas it is thrust aside. If the screen be raised, springs c c will rst beremoved from contact with plates d d and brought into contact with theexposed portions of blocks d d', thereby opening the circuit, includingbattery t'causing the operation of signal n. As the screen is stillfurther raised the springs c c will be brought into contact with wires bb, thus establishing a shunt-circuit about resistance s,

thereby causing the operation of signal Z. This shunt-circuit may betraced from the point through conductor Q, terminal c and wire Z1 uponthe right or left of the screen, and conductora, to ground. If desired,one of the guides l) may be made of other material than metal, in whichease one of the terminals f may be dispensed with.

The conductors q are inclosed in incasing strips of wood, securedto thetrame of the screen, which are placed close enough together to preventaccess between them.

My invention is susceptible of modifications which lnay be readily madeby those skilled in the art and may be applied to the protection ofobjeetsas well as openings. I do not therefore desire to be limited tothe precise construction shown; but,

Ilaving thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. In a burglar-alarm system the combination of a sliding cover adaptedto be placed over an opening or object, and having a mounting or supportwhich permits of its ready removal from its normal plane, with a circuitclosing or changing device adapted to be operated by said cover when thecover is shifted from its normal plane, a burglaralarm circuit includinga signal or alarm apparatus adapted to be actuated by the burglaralarmcircuit when altered by the operation of said circuit closing orchanging device, substantially as described.

2. In a burglar-alarm system the combination of a sliding cover adaptedto be placed over an opening or object, with a burglaralarm circuithaving one terminal mounted upon said cover and a second terminalstationarily supported with relation to said cover adapted to be broughtinto contact with the aforesaid terminal by the cover when it is shiftedfrom its normal plane whereby the condition of said circuit is altered,and a signaling or alarm apparatus adapted to be actuated by theburglar-alarm circuit when thus altered, substantially as described.

In a burglar-alarm system the combination of a sliding cover adapted tobe placed over an opening or object, and having a mounting or supportwhich permits of its ready removal from its normal plane, with aburglar-alarm circuit including alarm or signal apparatus and anartificial resistance, a circuit changing or closing device adapted tobe operated by said cover when the cover is shifted from its normalplane, and a shuntcircuit about said resistance adapted to be closed bysaid circuit changing or closing dcvice when thus operated, said signalapparatus being adapted to be operated by the bur glar-alarm circuitwhen thus altered, substantially as described.

4. In a burglar-alarm system the combination of a sliding cover adaptedto be placed over an opening or object, and a metallic guide b adaptedto direct said cover in its travel, with a plate f stationarilysupported and adapted to be brought into contact with guide l) by saidcover when it is shifted from its normal plane, a burglar-alarm circuitin cluding alarm orsignal apparatus and an artiicial resistance and anormally open shunt circuitabout said resistance having its terminals inguide b and plate f, substantially as and for the purpose described.

5. In a burglar-alarm system the combination of a sliding cover adaptedto be placed over an opening or object, with a metallic guide Z1 todirect said cover in its travel, terminal d supported upon but insulatedfrom said guide, terminal c carried upon the cover, a burglar-alarmcircuit normally completed through terminals d c said guide Z2 beingconnected with said circuit, alarm or signal apparatus included in saidcircuit, said terminal c being adapted to be removed from contact withterminal d to open the circuit, and then brought into contact withconductor ZJ to alter the circuit when the cover is being moved saidsignal apparatus being adapted to respond when the circuit is opened andaltered, substantially as described.

G. In a burglar-alarm system the combina- IOO TIO

tion of a sliding cover adapted to be placed over an opening or object,with a metal guide b to direct said cover in its travel, terminal dsupported upon but insulated from said lguide, terminal e carried uponthe cover, a burglar-alarm circuit including alarm apparatus and anartificial resistance normally completed through said terminals d e,said guide b and terminal e constituting terminals of a normally openpath of low resistance about said artificial resistance, said terminal ebeing adapted to be removed from terminal d and brought into contactWith conductor b as the cover is moved to rst open the circuit WILLIAMT. ARNOLD. I

Witnesses:

ALBERT LYNN LAWRENCE, GEORGE L. CRAGG.

